Saudi Arabia will need to spend 800 billion riyals, or more than $200 billion, over the next 10 years to meet skyrocketing demand for water and electricity, Saudi Arabia’s deputy electricity minister, Saleh al-Awaji, told an industry conference last month.

The population of Saudi Arabia, the world’s top oil exporting country, has climbed from 20 million in 2000 to 28.3 million in 2012, according to the World Bank. Adding to the pressure, water supply for cities and industries is heavily dependent on desalination, which consumes a lot of energy.

Demand for water and electricity has risen by 8 percent annually in the last few years, “to challenging levels,” Mr. Awaji said, according to local news reports. His investment figure of 800 billion riyals, taking into account a slew of recently announced new housing and infrastructure projects, was substantially higher than the government’s last official estimate, which put the requirement at 500 billion riyals by 2020.

Saudi Arabia consumed about three million barrels of oil per day in 2012, almost double 2000 levels, because of strong industrial growth and subsidized prices, according to an analysis by the United States Energy Information Administration. Oil-fired power plants now burn one million barrels a day of crude oil in the summer, when air-conditioning demand is at its peak, and the amount is rising. Natural gas liquids are increasingly used for petrochemical production.

A 2012 report by Chatham House, an independent policy research institute in London, warned that Saudi Arabia, which produced 11.1 million barrels of crude oil a day in 2011, could become a net oil importer by 2038. A Citigroup report the same year estimated that the kingdom could become an importer by 2022.

“At present, Saudi accounts for the bulk of OPEC spare capacity,” said Rachel Ziemba, an emerging markets economist at Roubini Global Economics. “A reduction in its exporting capabilities would weaken its role within OPEC as a swing producer.”

The diversion of oil from export markets to domestic energy generation could affect not only world supplies, but also the kingdom’s financial and social stability.

Crude oil for electricity production is priced at $4 a barrel. The export revenue lost by not selling it on the world market is more than $100 a barrel. The subsidy for power production, moreover, is just one of many. In general, prices for oil used domestically range from $5 to $15 per barrel.

“While 20 to 30 years down the line, the kingdom could be a net importer of oil, I’m more worried about a couple of years down the road when it may not be able to balance its budget,” said Taufiq Rahim, executive director of Globesight, a strategy consulting firm in Dubai. “Domestic consumption versus exports will become a national security concern, as the social welfare needs of the state will not be met without oil revenue.”

Saudi Arabia is planning a huge expansion in generating capacity, to 120 gigawatts by 2020 from 55 gigawatts now, with further increases in the years to 2032, according to the United States Energy Information Administration.

All the kingdom’s existing power plants are thermal — burning hydrocarbons like crude oil and fuel oil — but much of the proposed new capacity will be renewable, in part to free up oil for export. The plan calls for 41 gigawatts of solar generation and 14 gigawatts of other renewables to be installed by 2020. Planned increases to 2032 include 17 gigawatts of nuclear power, while efficiency improvements are expected to save the equivalent of an additional 37 gigawatts of capacity.

Unless demand is blunted, analysts and industry executives say, investment in renewable energy and energy efficiency, however ambitious, will not be enough to solve the problem.

“Cleaning air conditioners to be more fuel-efficient and building more insulated structures would temper demand growth, but an alternative would be to gradually cut domestic fuel subsidies,” Ms. Ziemba said.

“Renewable energy in any country’s energy mix is important; however, renewables are not a solution alone,” said Roberto Diego de Arozamena, of Abdul Latif Jameel Energy, which signed a joint venture with Fotowatio Renewable Venturesto develop solar energy projects in Saudi Arabia in January. “They have to coexist with conventional power sources to guarantee security of supply.”

Because of an editing error, an earlier version of this article misidentified the business led by Roberto Diego de Arozamena. Mr. Arozamena is chief executive of Abdul Latif Jameel Energy, not Fotowatio Renewable Ventures. (Those companies are working together to develop solar energy projects in Saudi Arabia.)